scholarly journals Box Experiment Study of Thermally Enhanced SVE for Benzene

2021 ◽  
Vol 18 (8) ◽  
pp. 4062
Author(s):  
Qixiang Zhang ◽  
Qiyan Feng ◽  
Xueqiang Zhu ◽  
Mei Zhang ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Concentration Distribution ◽  
Average Concentration ◽  
Soil Gas ◽  
Vapor Extraction ◽  
Operation Process ◽  
Repair Efficiency ◽  
Benzene Concentration ◽  
Benzene Content ◽  
Peak Value

In order to describe the changes of soil temperature field, air flow field and remediation situation with time during the process of thermally enhanced SVE (soil vapor extraction), a remediation experiment of benzene contaminated soil with single extraction pipe was carried out in a box device. The results showed that the whole temperature of the system was raised to 80 °C in 4 h. 43% of benzene were removed in the first 2% of the extraction time. After 24 h, the repair efficiency was close to 100%. The device can efficiently remove benzene from soil. By continuously monitoring the parameters in the operation process of the system, the spatial distribution of temperature and soil gas pollutant concentration with time was plotted. It showed the benzene concentration distribution in the soil gas was more consistent with the temperature distribution before the start of ventilation, and the concentration of benzene in the soil gas dropped rapidly after ventilation, while the temperature distribution was almost unaffected. In the treatment of soil with a benzene content of 17.8 mg∙kg−1, when the soil gas benzene concentration is the highest at 180 min, the peak value is 11,200 mg∙m−3, and the average concentration is 7629.4 mg∙m−3.

Migration of Anionic Species of Radioactive Cobalt through Soil

1989 ◽  
Vol 176 ◽  
Author(s):  
Toshihiko Ohnuki ◽  
David E. Robertson
Keyword(s):  
Concentration Distribution ◽  
Correlation Coefficients ◽  
Ionic Species ◽  
Average Concentration ◽  
Disposal Site ◽  
Retardation Factor ◽  
Laboratory Measurements ◽  
Waste Disposal Site ◽  
Anionic Species ◽  
Cross Correlations

ABSTRACTThe migration of an anionic species of 60Co through soil has been examined utilizing data on the migration of radionuclides leached from an aqueous waste disposal site. Correlation coefficients between concentrations of the anionic species of 60Co and those of the particulate, cationic and non-ionic species of 60Co reveal that the anionic species of 60Co was not interconverted from the other species during migration. The cross correlations of changes in the concentrations of the anionic species of 60Co with time between three different down gradient positions give a calculated retardation factor of the anionic species of 60Co of approximately 19, being 1200 times lower than the results of laboratory measurements. The average concentration distribution of the anionic species of 60Co suggests that the migration of the anionic species of 60Co consists of two migration fractions which were driven by different migration mechanisms.

scholarly journals Consequences of Soret–Dufour Effects, Thermal Radiation, and Binary Chemical Reaction on Darcy Forchheimer Flow of Nanofluids

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1421 ◽  
Author(s):  
Ghulam Rasool ◽  
Anum Shafiq ◽  
Dumitru Baleanu
Keyword(s):  
Temperature Distribution ◽  
Velocity Field ◽  
Thermal Radiation ◽  
Chemical Reaction ◽  
Concentration Distribution ◽  
Tabular Data ◽  
Data Form ◽  
Highly Nonlinear ◽  
Physical Quantities ◽  
Forchheimer Flow

This research article aims to investigate the consequences of binary chemical reaction, thermal radiation, and Soret–Dufour effects on a steady incompressible Darcy–Forchheimer flow of nanofluids. Stretching surface is assumed to drive the fluid along positive horizontal direction. Brownian motion, and the Thermophoresis are accounted in particular. The governing highly nonlinear system of problems which are advanced version of Navier–Stokes equations are transformed into ordinary differential equations (ODEs) using appropriately adjusted transformations invoking symmetric property of the independent variables. The numerical approach using RK45 in connection with shooting technique is adopted to solve the final equations. Graphical approach is used to interpret the results and the values of important physical quantities are given in tabular data form. Velocity field, temperature distribution and concentration distribution are graphically analyzed for variation in respective fluid parameters. Furthermore, density graphs and stream lines are sketched for the present model. The outputs indicate a rise of temperature field in connection with thermal radiation parameter. A clear decline is noticed in velocity field for elevated values of Forchheimer number and porosity factor. The Dufour effect anticipates a rising factor for temperature distribution and the same is noticed for concentration distribution in lieu of Soret effect. Thermal radiation and binary chemical reaction has strong impact on heat transport mechanism. The results for physical quantities such as skin friction, heat and mass flux rates are given in tabular data form in last section of this study.

scholarly journals Rn and CO<sub>2</sub> geochemistry of soil gas across the active fault zones in the capital area of China

2014 ◽  
Vol 14 (10) ◽  
pp. 2803-2815 ◽  
Author(s):  
X. Han ◽  
Y. Li ◽  
J. Du ◽  
X. Zhou ◽  
C. Xie ◽  
...  
Keyword(s):  
Active Fault ◽  
Emission Rate ◽  
Active Faults ◽  
Fault Zones ◽  
Average Concentration ◽  
Soil Gas ◽  
Spatiotemporal Variations ◽  
Gas Emission ◽  
Gas Sampling ◽  
Soil Gas Sampling

Abstract. The present work is proposed to investigate the spatiotemporal variations in soil gas Rn and CO2 across the active faults in the capital area of China in order to understand fault activities and assess seismic hazard. A total of 342 soil gas sampling sites were measured twice in 2011 and 2012 along seven profiles and across four faults. The results of soil gas surveys show that, in each profile, due to the variation in gas emission rate, the concentrations of Rn and CO2 changed in the vicinity of faults. Spatial distributions of Rn and CO2 in the study areas were different from each other, which was attributed to soil types affecting the existence of Rn and CO2. Compared with the measurement result of 2011, the increasing amplitude of average concentration value of Rn and CO2 in profiles in 2012 ranged from 30.2 to 123.4% and 66.3 to 131.7%, respectively, which were coincident with the enhancement of seismic activities in the capital area of China. Our results indicate that special attention with regard to seismic monitoring should be paid to the Xinbaoan–Shacheng Fault and the northeastern segment of the Tangshan Fault in the future.

scholarly journals Methods for Prediction of Temperature Distribution in Flashover Caused by Backdraft Fire

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Guowei Zhang ◽  
Guoqing Zhu ◽  
Guanglin Yuan ◽  
Lili Huang
Keyword(s):  
Temperature Distribution ◽  
Temperature Curve ◽  
Peak Temperature ◽  
Office Building ◽  
Temperature Peak ◽  
Experiment Data ◽  
Building Process ◽  
Fire Experiment ◽  
Fire Experiments ◽  
Peak Value

Accurately predicting temperature distribution in flashover fire is a key issue for evacuation and fire-fighting. Now many good flashover fire experiments have be conducted, but most of these experiments are proceeded in enclosure with fixed openings; researches on fire development and temperature distribution in flashover caused by backdraft fire did not receive enough attention. In order to study flashover phenomenon caused by backdraft fire, a full-scale fire experiment was conducted in one abandoned office building. Process of fire development and temperature distribution in room and corridor were separately recorded during the experiment. The experiment shows that fire development in enclosure is closely affected by the room ventilation. Unlike existing temperature curves which have only one temperature peak, temperature in flashover caused by backdraft may have more than one peak value and that there is a linear relationship between maximum peak temperature and distance away from fire compartment. Based on BFD curve and experimental data, mathematical models are proposed to predict temperature curve in flashover fire caused by backdraft at last. These conclusions and experiment data obtained in this paper could provide valuable reference to fire simulation, hazard assessment, and fire protection design.

scholarly journals National and sub-national estimation of benzene emission trend into atmosphere in Iran from 1990 to 2013

2020 ◽  
Author(s):  
Mansour Shamsipour ◽  
Mina Aghaei ◽  
Safa Kalteh ◽  
Mohammad Sadegh Hassanvand ◽  
Kimiya Gohari ◽  
...  
Keyword(s):  
Field Studies ◽  
Upward Trend ◽  
Policy Makers ◽  
Adverse Health Effects ◽  
The Past ◽  
Concentration Estimation ◽  
Benzene Concentration ◽  
Benzene Content ◽  
Insight Into

Introduction: Exposure to benzene has been associated with a range of acute and long-term adverse health effects. We aimed to estimate national and provincial level of benzene emissions from 1990 to 2013 in Iran. Materials and methods: Benzene emission was estimated through two main sources: unburned benzene content of fuel and evaporated benzene. Unburned benzene content of fuel estimated by gasoline consumption rate, kilometers traveled by non-diesel-based cars, and benzene emission factor. Evaporated benzene estimated by evaporated gasoline and volumetric percentile of benzene.               Results: The estimated provincial annual mean benzene estimation range was between 5.9 (ton) and 1590 (ton) from 1990 to 2013. Our results showed that maximum benzene emission over the past 24 years occurred in Tehran, (Mean± SD) (1147.2±308.5) (ton)), Isfahan (423.4±132) (ton)), Khorasan Razavi (410.4±122.2) (ton)) provinces, respectively. There was an upward trend in the benzene emission into atmosphere at national and subnational level from 1990 to 2007. Also a significant decrease trend is observed from 2008 to 2013. Conclusion: The findings of this study will provide an insight into the extent of emitted benzene in the atmosphere at different regions of Iran for policy makers and scientists and may be a groundwork for field studies on benzene concentration estimation.

scholarly journals DIFFERENCES CONCENTRATION DISTRIBUTION AND SOURCE OF IN ORGANOCHLORINE PESTICIDES IN WATER AND SEDIMENT IN JAKARTA BAY WATERS DURING TRANSITION SEASON

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Khozanah Khozanah
Keyword(s):  
Water Column ◽  
Organochlorine Pesticides ◽  
Concentration Distribution ◽  
Average Concentration ◽  
Dry Season ◽  
Electron Capture Detection ◽  
Agricultural Activities ◽  
Transition Season ◽  
Water And Sediment ◽  
Pesticides In Water

Study on the distribution and sources of organochlorine pesticide concentrations in water samples and sediments from the Jakarta Bay was conducted in April 2011 (transition season I) and June 2011 (dry season). The purpose of this study was to determine the distribution of pesticide concentrations in water and sediments and to identify possible sources of organochlorine pesticides. The concentrations of organochlorine pesticides was measured by the GC/ECD (electron capture detection) HP 5890 series II. Concentrations found in the water column during transition I season ranged from 11.596 to 74.338 ng/l (average=41.998 ng/l) and in dry season varied from 4.554 to 19.119 ng/l (average=7.741 ng/l). In sediment samples, concentrations found in transition I season varied from 0.936 to 2.816 ng/g (average=1.782 ug/g), and in dry season about 0.7691 to 7.138 ug/g, (average=2.722 ug/g). In the water column, the average concentration in transition I was higher than that found in dry season, whereas levels in sediment during transition season I was lower. The average levels of pesticides in the water column was higher than those found in sediments. These results suggested that the seasons played a role in the distribution of organochlorine pesticides in the water column and sediments. Source of organochlorine pesticides were suggested from agricultural activities in the mainland Cisadane. Keywords: organochlorine pesticides,  DDT, BHC, Jakarta Bay waters.

Influence of Emergency Stop Operation for Strength of Brazed Structure With Rectangular Fins and Plates in Liquefied Natural Gas Heat Exchanger

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Hongqiang Ma ◽  
Xingpeng Song ◽  
Yemin Liu ◽  
Nuo Liang ◽  
Jianping Han ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Equivalent Stress ◽  
Liquefied Natural Gas ◽  
Structural Safety ◽  
Operation Process ◽  
Brazed Joints ◽  
Emergency Stop ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
Peak Value

Abstract In order to ensure the structural safety of a liquefied natural gas (LNG) heat exchanger in emergency stop operation process, the strength of a brazed structure with rectangular fins and plates is investigated by means of the finite element method. The microstructure of brazed joints and brazing filler is tested by metallographic examination with a scanning electron microscope (SEM). The results show that the maximum shear stress is the main reason for the structural failure at the brazing seam while the brazed joint is mainly subjected to the maximum normal stress. The peak value of the Von Mises equivalent stress in brazed structure with rectangular fins and plates linearly increases with the HMR pressure when the temperature difference is less than 10 K between HMR and LMR. At the same time, the peak value of Von Mises equivalent stress also increases with the equilibrium temperature and temperature difference between LMR and HMR. The aggregation of the elemental Si in the brazed joints and brazing seam will exacerbate the structural safety of the brazed structure in the emergency stop operation process. The above results provide some constructive guidance for the emergency stop operational process for an LNG heat exchanger.

Soil Gas Sampling for 1,4-Dioxane during Heated Soil Vapor Extraction

2018 ◽  
Vol 38 (1) ◽  
pp. 85-89
Author(s):  
David R. Burris ◽  
Paul R. Dahlen ◽  
Robert E. Hinchee
Keyword(s):  
Soil Gas ◽  
Soil Vapor Extraction ◽  
Vapor Extraction ◽  
Gas Sampling ◽  
Heated Soil ◽  
Soil Gas Sampling

scholarly journals DIFFERENCES CONCENTRATION DISTRIBUTION AND SOURCE OF IN ORGANOCHLORINE PESTICIDES IN WATER AND SEDIMENT IN JAKARTA BAY WATERS DURING TRANSITION SEASON

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Khozanah Khozanah
Keyword(s):  
Water Column ◽  
Organochlorine Pesticides ◽  
Concentration Distribution ◽  
Average Concentration ◽  
Dry Season ◽  
Electron Capture Detection ◽  
Agricultural Activities ◽  
Transition Season ◽  
Water And Sediment ◽  
Pesticides In Water

<p>Study on the distribution and sources of organochlorine pesticide concentrations in water samples and sediments from the Jakarta Bay was conducted in April 2011 (transition season I) and June 2011 (dry season). The purpose of this study was to determine the distribution of pesticide concentrations in water and sediments and to identify possible sources of organochlorine pesticides. The concentrations of organochlorine pesticides was measured by the GC/ECD (electron capture detection) HP 5890 series II. Concentrations found in the water column during transition I season ranged from 11.596 to 74.338 ng/l (average=41.998 ng/l) and in dry season varied from 4.554 to 19.119 ng/l (average=7.741 ng/l). In sediment samples, concentrations found in transition I season varied from 0.936 to 2.816 ng/g (average=1.782 ug/g), and in dry season about 0.7691 to 7.138 ug/g, (average=2.722 ug/g). In the water column, the average concentration in transition I was higher than that found in dry season, whereas levels in sediment during transition season I was lower. The average levels of pesticides in the water column was higher than those found in sediments. These results suggested that the seasons played a role in the distribution of organochlorine pesticides in the water column and sediments. Source of organochlorine pesticides were suggested from agricultural activities in the mainland Cisadane.</p> <p>Keywords: organochlorine pesticides,  DDT, BHC, Jakarta Bay waters.</p>

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