scholarly journals Spatial Characteristics and Regional Transmission Analysis of PM2.5 Pollution in Northeast China, 2016–2020

2021 ◽  
Vol 18 (23) ◽  
pp. 12483
Author(s):  
Chunsheng Fang ◽  
Liyuan Wang ◽  
Zhuoqiong Li ◽  
Ju Wang
Keyword(s):  
Northeast China ◽  
Industrial Development ◽  
Mean Value ◽  
Liaoning Province ◽  
Hotspot Analysis ◽  
Annual Average ◽  
Air Mass ◽  
Average Value ◽  
Air Mass Trajectories ◽  
Pm2.5 Concentration

Northeast China is an essential industrial development base in China and the regional air quality is severely affected by PM2.5 pollution. In this paper, spatial autocorrelation, trajectory clustering, hotspot analysis, PSCF and CWT analysis are used to explore the spatial pollution characteristics of PM2.5 and determine the atmospheric regional transmission pattern for 40 cities in Northeast China from 2016 to 2020. Analysis of PM2.5 concentration characteristics in the northeast indicates that the annual average value and total exceedance days of PM2.5 concentration in Northeast China showed a U-shaped change, with the lowest annual average PM2.5 concentration (31 μg/m3) in 2018, decreasing by 12.1% year-on-year, and the hourly PM2.5 concentration exploding during the epidemic lockdown period in 2020. A stable PM2.5 pollution band emerges spatially from the southwest to Northeast China. Spatially, the PM2.5 in Northeast China has a high degree of autocorrelation and a south-hot–north-cool characteristic, with all hotspots concentrated in the most polluted Liaoning province, which exhibits the H–H cluster pattern and hotspot per year. Analysis of the air mass trajectories, potential source contributions and concentration weight trajectories in Northeast China indicates that more than 74% of the air mass trajectories were transmitted to each other between the three heavily polluted cities, with the highest mean value of PM2.5 pollution trajectories reaching 222.4 μg/m3, and the contribution of daily average PM2.5 concentrations exceeding 60 μg/m3 within Northeast China. Pollution of PM2.5 throughout the Northeast is mainly influenced by short-range intra-regional transport, with long-range transport between regions also being an essential factor; organized integration is the only fundamental solution to air pollution.

scholarly journals Spatial-Temporal Evolution of PM2.5 Concentration and its Socioeconomic Influence Factors in Chinese Cities in 2014–2017

2019 ◽  
Vol 16 (6) ◽  
pp. 985 ◽  
Author(s):  
Yazhu Wang ◽  
Xuejun Duan ◽  
Lei Wang
Keyword(s):  
Industrial Development ◽  
Population Distribution ◽  
Influence Factors ◽  
Mean Value ◽  
Chinese Government ◽  
Chinese Cities ◽  
Average Value ◽  
Concentration Changes ◽  
Peripheral Areas ◽  
Pm2.5 Concentration

PM2.5 is a main source of China’s frequent air pollution. Using real-time monitoring of PM2.5 data in 338 Chinese cities during 2014–2017, this study employed multi-temporal and multi-spatial scale statistical analysis to reveal the temporal and spatial characteristics of PM2.5 patterns and a spatial econometric model to quantify the socio-economic driving factors of PM2.5 concentration changes. The results are as follows: (1) The annual average value of PM2.5 concentration decreased year by year and the monthly average showed a U-shaped curve from January to December. The daily mean value of PM2.5 concentration had the characteristics of pulse-type fluctuation and the hourly variation presented a bimodal curve. (2) During 2014–2017, the overall PM2.5 pollution reduced significantly, but that of more than two-thirds of cities still exceeded the standard value (35 μg/m3) regulated by Chinese government. PM2.5 pollution patterns showed high values in central and eastern Chinese cities and low values in peripheral areas, with the distinction evident along the same line that delineates China’s uneven population distribution. (3) Population agglomeration, industrial development, foreign investment, transportation, and pollution emissions contributed to the increase of PM2.5 concentration. Urban population density contributed most significantly while economic development and technological progress reduced PM2.5 concentration. The results also suggest that China in general remains a “pollution shelter” for foreign-funded enterprises.

scholarly journals Radon survey in kindergartens and schools of Dushanbe, Republic of Tajikistan

2021 ◽  
Vol 14 (1) ◽  
pp. 124-132
Author(s):  
S. V. Muminov ◽  
B. B. Barotov ◽  
M. M. Makhmudova ◽  
F. A. Khamidov ◽  
M. Z. Akhmedov ◽  
...  
Keyword(s):  
Warm Season ◽  
Geological Structure ◽  
Mean Value ◽  
Heating Season ◽  
Annual Average ◽  
Average Value ◽  
Limit Value ◽  
Equivalent Concentration ◽  
Radon Survey ◽  
Equilibrium Equivalent Concentration

The paper presents results of the radon survey carried out in preschool and school institutions in Dushanbe, Republic of Tajikistan. Radon concentration was measured using solid state nuclear track detectors Radtrak2. Track detectors were exposed for 3 months during the heating and warm seasons of the year in the same premises. In total, the measurements were performed in 200 premises of 14 kindergartens and 36 schools. The radon equilibrium equivalent concentration during the heating and warm seasons and the annual average radon equilibrium equivalent concentration were calculated. Annual average radon equilibrium equivalent concentration in surveyed buildings ranged from 42 to 331 Bq/m3 with the mean value of 98 Bq/m3 on the first floor and 56 Bq/m3 on the second floor. It was shown that both seasonal values and annual average value of radon equilibrium equivalent concentration in the premises on the second floor are lower than in the premises on the first floor. The annual average effective dose to children from exposure to radon and its progeny in the premises of schools and kindergartens in Dushanbe ranged from 0,64 to 1,64 mSv. The limit value of annual average radon equilibrium equivalent concentration in dwellings and public buildings is set to 100 Bq/m3 for newly built buildings and 200 Bq/m3 for existing buildings in the Radiation safety norms (NRB-06) of the Republic of Tajikistan. This limit was exceeded only on the first floors in one kindergarten during the heating season, in three schools during the warm season and in eight schools during the heating season. When comparing the results of measurements of radon equilibrium equivalent concentration with data on the geological structure of underlying rocks at the locations of the surveyed buildings, no regularity was found. Additional detailed measurements in the buildings, including basements, will help to identify the source of radon entry into the indoor air and to develop recommendations for implementing radon remediation actions separately for each building. The survey results were also used to develop a radon map of Dushanbe.

scholarly journals Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

2021 ◽  
Author(s):  
Xiaoyi Shen ◽  
Chang-Qing Ke ◽  
Bin Cheng ◽  
Wentao Xia ◽  
Mengmeng Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Reanalysis Data ◽  
Mean Value ◽  
Ocean Model ◽  
North Coast ◽  
Average Value ◽  
The North ◽  
Wind Sea ◽  
The One

AbstractIn August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled ice-ocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978 (mean value of 1.1 m, compared to the average value of 2.8 m during 1978–2017) and the modest southerly wind caused by a positive North Atlantic Oscillation (mean value of 0.82, compared to the climatological value of −0.02) were responsible for the formation and maintenance of this polynya. The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind. Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

Resistance of a Ship Undergoing Oscillatory Motion

2010 ◽  
Vol 54 (02) ◽  
pp. 120-132
Author(s):  
Lawrence J. Doctors ◽  
Alexander H. Day ◽  
David Clelland
Keyword(s):  
Finite Depth ◽  
Mean Value ◽  
Wave Resistance ◽  
General Effect ◽  
Towing Tank ◽  
Ship Model ◽  
Average Value ◽  
Unsteady Effects ◽  
Oscillatory Cycle ◽  
Resistance Tests

In this paper, we describe extensions to the research of Doctors et al. (Doctors, L. J., Day, A. H., and Clelland, D., 2008, Unsteady effects during resistance tests on a ship model in a towing tank, Journal of Ship Research, 52, 4, 263–273) and Day et al. (Day, A. H., Clelland, D., and Doctors, L. J., 2009, Unsteady finite-depth effects during resistance tests in a towing tank, Journal of Marine Science and Technology, 14, 3, 387–397) in which the oscillations in the wave resistance during the constant-velocity phase of a towing-tank resistance test on a ship model were measured and predicted, in the cases of relatively deep and relatively shallow water. In the current study, the ship model was towed with a harmonic velocity component superimposed on the usual constant forward velocity. This work constitutes a first step in the understanding of the unsteady hydrodynamics of a racing shell (rowing boat). We show here that the unsteady wave resistance varies considerably from the traditional (steady) average value. Indeed, the wave resistance is frequently negative during part of the oscillatory cycle. However, the general effect is an increase in the temporal mean value of the wave resistance; this suggests that every effort should be made to reduce the unsteadiness of the motion. We also demonstrate that the unsteady wave-resistance theory provides an excellent prediction of the measured effects summarized here. These predictions are often within a few percent of the measured values of the resistance.

scholarly journals Prevalence and time trends of spina bifida in fourteen cities located in the Liaoning province of northeast China, 2006-2015

Oncotarget ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 18943-18948
Author(s):  
Gen Ba ◽  
Qi-Jun Wu ◽  
Yan-Ling Chen ◽  
Yan-Hong Huang ◽  
Ting-Ting Gong
Keyword(s):  
Spina Bifida ◽  
Northeast China ◽  
Time Trends ◽  
Liaoning Province

scholarly journals Mandibular Morphology Differences Between Edentulous And Dentate Assessed By Panoramic Radiographs

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Lidya Irani Nainggolan ◽  
Aude Layakni Girsang
Keyword(s):  
Panoramic Radiography ◽  
Mechanical Stimulus ◽  
Mean Value ◽  
Notch Depth ◽  
Cross Sectional ◽  
Gonial Angle ◽  
Average Value ◽  
Mandibular Morphology ◽  
Edentulous Patients ◽  
Ramus Height

Introduction: Facial profile can be influenced by edentulous condition that can change mandibular morphology that can affect mastication, digestion and psychosocial life. Edentulism causes absence of occlusal mechanical stimulus, decrease the activity of mastication muscles and increase mandibular bone resorption. These changes can be assessed using panoramic radiography by looking at the vertical dimension of the head of the condyle and its shape, ramus, and the angle of the mandible. The aim of the study was to assess the mean value and differences of mandibular morphology in edentulous and dentate patients using panoramic radiography. Materials and Methods: This was an analytical study with cross-sectional approach using purposive sampling methods. 50 dentate and edentulous patients who came to Dentistry Hospital of University of Sumatera Utara were used as sample. Data analysis was done using Independent T test and MannWhitney test. Results: Results showed that the average value of gonial angle, ramus height, condylar height, antegonial notch depth and ramus notch depth in edentulous patients were 125,38 ± 9,51; 35.98mm ± 4.26; 5.58mm ± 0.90; 2.11mm ± 1.04; and 2.73mm ± 0, 88, and the results showed that the average value of mandibular morphology in dentate patients were 123.34 ± 7.07; 38.15mm ± 3.23; 6.95mm ± 1.25; 1.41mm ± 0.77; and 2.15mm ± 0.59. Conclusion(s): There were significant differences in the values of ramus height, condylar height, antegonial notch depth, and ramus notch depth. Difference was also found in gonial angle value, but was not statistically significant.

scholarly journals Pengembangan LKPD Tema Tanah Airku Sub Tema Kota Palembang untuk Anak Kelompok B

2019 ◽  
Vol 1 (2) ◽  
pp. 129-141
Author(s):  
Gustiana Yuantini ◽  
Hasmalena Hasmalena ◽  
Syafdaningsih Syafdaningsih
Keyword(s):  
Small Group ◽  
Mean Value ◽  
Average Score ◽  
Self Evaluation ◽  
Average Value ◽  
Expert Review ◽  
Group Evaluation ◽  
Observation Methods ◽  
Evaluation Stage ◽  
Group B

This research aims to develop valid and practical student worksheet. Subjects in this research were B2 and B3 groups in state kindergarten of Pembina 2 Palembang. The model developed in this development was Rowntree consisting of One to one evaluation and small group evaluation. It was aimed to see the practicality and it used the Tessmer evaluation stage which consisted of self evaluation, expert review. Data collection techniques used in this research were interview, walkthrough and observation methods. According to the results of the research, it showed that the validity of the material and design obtained an average value of 3.77 in very valid categories. Student worksheet practicality test in terms of observations with a mean value of 95% in very practical category. The small group evaluation stage obtained an average score of 92% in the very practical category. Questionnaire result was 97% in valid category. From the result, it can be concluded that student worksheet theme of my homeland and sub-theme of Palembang city for group B children is valid and practical. It is also worth to use as learning student worksheet with Theme of my homeland

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