Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Concrete batching plants are a typical source of fugitive dust in Beijing. In this study, two concrete batching plants in Beijing were used to test wind erosion of dust with a Portable In-suit Wind Erosion Laboratory (PI-SWERL) designed by the Desert Research Institute (DRI). Sand and aggregate storage piles and paved roads in concrete batching plants were tested to determine the emission characteristics of wind eroded dust. Combining the frequencies of disturbance of storage piles and paved road surface with local meteorological data, localized wind erosion dust emission factors of PM were established. Results demonstrate that:①There are small differences in daily average emission factors for PM between the aggregate warehouse entrance area, concrete loading area, social road import area, and concrete batching plant entrance area, with these being 0.45, 0.41, 0.31, and 0.30 kg·(hm·d), respectively. ②Daily average emission factors for PM of coarse stone, fine stone, coarse sand, and fine sand storage piles are 0.10, 0.12, 0.26, and 2.02 kg·(hm·d), respectively. Emission factors of fine sand storage piles are 20.5, 16.8, and 7.7 times greater than those of coarse stone, fine stone, and coarse sand, respectively, and spring emission factors are 6.4, 3.4, and 1.3 times greater than those of summer, autumn, and winter, respectively. ③Daily average emission factors for PM of storage piles and paved roads are 1.13 and 0.37 kg·(hm·d), respectively 3.9 and 1.3 times higher than the wind erosion factor from storage piles from AP-42 files (c11s12 concrete batching, 1995); the uncertainty range of the emission factor is 34%-92%. ④It is recommended to strengthen watering, sweeping, and cleaning of paved roads, and to ensure fully enclosed storage and use of spray water to reduce wind erosion of dust from storage piles, especially from fine sand piles.
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Source |
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http://dx.doi.org/10.13227/j.hjkx.201801024 | DOI Listing |
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