scholarly journals Size-Segregated Chemical Compositions of HULISs in Ambient Aerosols Collected during the Winter Season in Songdo, South Korea

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 226 ◽  
Author(s):  
Kyoung-Soon Jang ◽  
A Young Choi ◽  
Mira Choi ◽  
Hyunju Kang ◽  
Tae-Wook Kim ◽  
...  
Keyword(s):  
South Korea ◽  
Winter Season ◽  
Sampling Period ◽  
Primary Objective ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Ion Cyclotron Resonance ◽  
Heating Period ◽  
Ambient Aerosols ◽  
Air Sampler

The primary objective of this study was to investigate the molecular compositions of humic-like substances (HULISs) in size-resolved ambient aerosols, which were collected using an Anderson-type air sampler (eight size cuts between 0.43 and 11 μm) during the winter season (i.e., the heating period of 8–12 January 2018) in Songdo, South Korea. The aerosol samples collected during the pre- (preheating, 27 November–1 December 2017) and post-winter (postheating, 12–16 March 2018) periods were used as controls for the winter season samples. According to the concentrations of the chromophoric organics determined at an ultraviolet (UV) wavelength of 305 nm, most of the HULIS compounds were found to be predominantly enriched in particles less than 2.1 μm regardless of the sampling period, which shows that particulate matter (diameter less than 2.5 μm; PM2.5) aerosols were the dominant carriers of airborne organics. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (UHR FT–ICR MS) analysis of the aerosol-carried organic substances revealed that as the aerosol size increased the proportions of CHO and nitrogen-containing CHO (CHON) compounds decreased, while the proportion of sulfur-containing CHO (CHOS) species increased. In particular, the ambient aerosols during the heating period seemed to present more CHO and CHON and less CHOS molecules compared to aerosols collected during the pre- and postheating periods. The aerosols collected during the heating period also exhibited more aromatic nitrogen-containing compounds, which may have originated from primary combustion processes. Overall, the particle size distribution was likely influenced by source origins; smaller particles are likely from local sources, such as traffic and industries, and larger particles (i.e., aged particles) are likely derived from long-range transport generating secondary organic aerosols (SOAs) in the atmosphere. The results of the size-segregated particles can be utilized to understand particle formation mechanisms and shed light on their toxicity to human health.

scholarly journals Changes in Air Temperature and Snow Cover in Winter in Poland

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Katarzyna Szyga-Pluta
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Winter Season ◽  
Primary Objective ◽  
Climatic Conditions ◽  
Cover Depth ◽  
North Eastern ◽  
Northern Regions ◽  
Maximum Air Temperature ◽  
Snow Cover Depth

The primary objective of the paper was to characterize the climatic conditions in the winter season in Poland in the years 1966/67–2019/20. The study was based on daily values of minimum (Tmin) and maximum air temperature (Tmax), and daily values of snow cover depth. The study showed an increase in both Tmin and Tmax in winter. The most intensive changes were recorded in north-eastern and northern regions. The coldest winters were recorded in the first half of the analyzed multiannual period, exceptionally cold being winters 1969/70 and 1984/85. The warmest winters occurred in the second half of the analyzed period and among seasons with the highest mean Tmax, particularly winters 2019/20 and 1989/90 stood out. In the study period, a decrease in snow cover depth statistically significant in the majority of stations in Poland was determined, as well as its variability both within the winter season and multiannual.

Evaluation of Chemical Compositions of Lycoris radiata at Different Development Stages and Cultivation Sites in South Korea

2013 ◽  
Vol 25 (16) ◽  
pp. 9073-9078
Author(s):  
J.-H. Chun ◽  
I.-H. Jang ◽  
N.A. Al-Dhabi ◽  
D.-G. Lee ◽  
M. Valan Arasu ◽  
...  
Keyword(s):  
South Korea ◽  
Chemical Compositions ◽  
Development Stages ◽  
Lycoris Radiata

scholarly journals The Mineral Chemistry of Chlorites and Its Relationship with Uranium Mineralization from Huangsha Uranium Mining Area in the Middle Nanling Range, SE China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 199 ◽  
Author(s):  
Dehai Wu ◽  
Jiayong Pan ◽  
Fei Xia ◽  
Guangwen Huang ◽  
Jing Lai
Keyword(s):  
Mining Area ◽  
Uranium Mining ◽  
Uranium Mineralization ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Type I ◽  
Low Oxygen ◽  
Nanling Range ◽  
The Relationship ◽  
Uranium Mining Area

The Huangsha uranium mining area is located in the Qingzhangshan uranium-bearing complex granite of the Middle Nanling Range, Southeast China. This uranium mining area contains three uranium deposits (Liangsanzhai, Egongtang, and Shangjiao) and multiple uranium occurrences, showing favorable mineralization conditions and prospecting potential for uranium mineral resources. Chloritization is one of the most important alteration types and prospecting indicators in this mining area. This study aims to unravel the formation environment of chlorites and the relationship between chloritization and uranium mineralization, based on detailed field work and petrographic studies of the wallrock and ore samples from the Huangsha uranium mining area. An electron probe microanalyzer (EPMA) was used in this study to analyze the paragenetic association, morphology, and chemical compositions of chlorite, to classify chemical types and to calculate formation temperatures and n(Al)/n(Al + Mg + Fe) values of chlorite. The formation mechanism and the relationship with uranium mineralization of the uranium mining area are presented. Some conclusions from this study are: (1) There are five types of chlorites, including the chlorite formed by the alteration of biotite (type-I), by the metasomatism of feldspar with Fe–Mg hydrothermal fluids (type-II), chlorite vein/veinlet filling in fissures (type-III), chlorite closely associated with uranium minerals (type-IV), and chlorite transformed from clay minerals by adsorbing Mg- and Fe-components (type-V). (2) The chlorite in the Huangsha uranium mining area belongs to iron-rich chlorite and is mainly composed of chamosite, partly clinochlore, which are the products of multiple stages of hydrothermal action. The original rocks are derived from argillite, and their formation temperatures vary from 195.7 °C to 283.0 °C, with an average of 233.2 °C, suggesting they formed under a medium to low temperature conditions. (3) The chlorites were formed under reducing conditions with low oxygen fugacity and relatively high sulfur fugacity through two formation mechanisms: dissolution–precipitation and dissolution–migration–precipitation; (4) The chloritization provided the required environment for uranium mineralization, and promoted the activation, migration, and deposition of uranium.

scholarly journals SO<sub>2</sub> and NH<sub>3</sub> emissions enhance organosulfur compounds and fine particle formation from the photooxidation of a typical aromatic hydrocarbon

2021 ◽  
Vol 21 (10) ◽  
pp. 7963-7981
Author(s):  
Zhaomin Yang ◽  
Li Xu ◽  
Narcisse T. Tsona ◽  
Jianlong Li ◽  
Xin Luo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Oxidation Mechanism ◽  
Particle Formation ◽  
Urban Atmosphere ◽  
Mass Spectrometry Analysis ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Organosulfur Compounds ◽  
Aerosol Formation ◽  
Secondary Aerosol

Abstract. Aromatic hydrocarbons can dominate the volatile organic compound budget in the urban atmosphere. Among them, 1,2,4-trimethylbenzene (TMB), mainly emitted from solvent use, is one of the most important secondary organic aerosol (SOA) precursors. Although atmospheric SO2 and NH3 levels can affect secondary aerosol formation, the influenced extent of their impact and their detailed driving mechanisms are not well understood. The focus of the present study is to examine the chemical compositions and formation mechanisms of SOA from TMB photooxidation influenced by SO2 and/or NH3. Here, we show that SO2 emission could considerably enhance aerosol particle formation due to SO2-induced sulfate generation and acid-catalyzed heterogeneous reactions. Orbitrap mass spectrometry measurements revealed the generation of not only typical TMB products but also hitherto unidentified organosulfates (OSs) in SO2-added experiments. The OSs designated as being of unknown origin in earlier field measurements were also detected in TMB SOA, indicating that atmospheric OSs might also be originated from TMB photooxidation. For NH3-involved experiments, results demonstrated a positive correlation between NH3 levels and particle volume as well as number concentrations. The effects of NH3 on SOA composition were slight under SO2-free conditions but stronger in the presence of SO2. A series of multifunctional products with carbonyl, alcohols, and nitrate functional groups were tentatively characterized in NH3-involved experiments based on infrared spectra and mass spectrometry analysis. Plausible formation pathways were proposed for detected products in the particle phase. The volatility distributions of products, estimated using parameterization methods, suggested that the detected products gradually condense onto the nucleation particles to contribute to aerosol formation and growth. Our results suggest that strict control of SO2 and NH3 emissions might remarkably reduce organosulfates and secondary aerosol burden in the atmosphere. Updating the aromatic oxidation mechanism in models could result in more accurate treatment of particle formation for urban regions with considerable SO2, NH3, and aromatics emissions.

scholarly journals Effect of probiotics on stool characteristic of bottle fed infants

2019 ◽  
Vol 9 (3) ◽  
pp. 157
Author(s):  
Yoo Mi Lee ◽  
Young Sun Cho ◽  
Su Jin Jeong
Keyword(s):  
Breast Milk ◽  
South Korea ◽  
Lactobacillus Plantarum ◽  
Medical Center ◽  
Sole Source ◽  
Primary Objective ◽  
Stool Frequency ◽  
Once Daily ◽  
Bristol Stool Scale ◽  
Secondary Objective

Background: Approximately 70% of all newborns in South Korea are fed a commercial formula as their sole source of nutrition or as a supplement to breast milk. It is common for many formula-fed infants to be switched from one formula to another because of perceived abnormalities in stooling patterns (too much/too little, too hard/too loose). Also, probiotics may have been recommended by a clinician or practitioner when there is thought to be a problem with the babies stool based on many reports.Aims: The primary objective of this study was to determine whether probiotic (nLp-nF1) exposure during the first 6 months of life is safe. The secondary objective was to assess if nF1 exposure correlated with changes in formula-fed infants’ stool characteristics.Result: We recruited 49 healthy formula-fed infants aged 0-6 months from Bundang Cha Medical Center. Infants were given a 14-day supply of probiotics (nf1: Lactobacillus plantarum 2.5 X 1010/g/pack, 2 pack/day). The overall rate of stool change after probiotics is 83% (41/49). Among them, 75.6% (31/41) participants answered fairly about the change of stool characteristics. The significant change of stool frequency, stool color and flatulence after probiotics intervention was reported. The number of infants who defecated once daily was increased from 53% (26 of 49) to 77.5% (38 of 49) (P=0.075). Mustard yellow colored feces increased from 22 to 40 (p=0.018). Only 9 out of 20 infants with flatulence (>3 times) showed persistence of symptoms after probiotics (p<0.001). After taking probiotics, Bristol Stool Scale 4-5 stool was reported from 23 to 37(p=0.018).Conclusion: By taking probiotics, the color of the stool changed, and the incidence of flatulence production decreased. Although the results are not statistically significant, the quality and quantity of stool improved according to the Bristol Stool Scale.Keywords: Probiotics, Bristol Stool Scale, stool

scholarly journals Hydrogeochemistry, Geothermometry, and Genesis of the Hot Springs in the Simao Basin in Southwestern China

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-23 ◽  
Author(s):  
Yuqi Zhang ◽  
Xun Zhou ◽  
Haisheng Liu ◽  
Mingxiao Yu ◽  
Kuo Hai ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Hot Springs ◽  
Cold Water ◽  
Metamorphic Rocks ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Red Beds ◽  
Incongruent Dissolution ◽  
Geothermal Waters ◽  
Isotopic Analyses

In the Simao Basin in southwest China widely occur red beds of poor permeability. Nevertheless, more than 100 springs exist in the basin, some of which are hot springs with varying temperature. Hot springs contain abundant information on hydrogeochemical processes and groundwater circulation. In this study, hydrochemical and isotopic analyses and mixed models are used to examine the sources of recharge, heat, and solutes of the hot springs to better understand the subsurface processes and formation mechanisms of different hot springs in the basin. Three types of springs are found in the Simao Basin: springs of HCO3-Na type occur in the metamorphic rocks, springs of HCO3-Ca(Mg) and Cl-HCO3-Na-Ca types in the carbonate rocks, and springs of Cl(SO4)-SO4(Cl)-HCO3-Na(Ca) type in the red beds. Data of δ2H and δ18O indicate that the hot springs in the Simao Basin are meteoric in origin. Incongruent dissolution is the dominant process affecting the chemical compositions of the spring waters. The hydrochemical constituents of the hot springs in the metamorphic rocks, carbonate rocks, and red beds are influenced by the weathering of albite and the dissolution of carbonate, gypsum, anhydrite, and halite. The geothermal waters are mixed with shallow cold waters in their ascending processes, and the mixing ratios of cold water range from 58% to 94%. Due to the effect of mixing, the reservoir temperatures (51°C-127°C) calculated with the quartz geothermometer are regarded as the minimum reservoir temperatures. More reliable reservoir temperatures (91°C-132°C) are estimated with the fixed-Al method. The following mechanisms contribute to the formation of hot springs in the Simao Basin: the groundwater receives recharge from infiltration of precipitation and undergoes deep circulation, during which groundwater is heated by heat flow and incongruently dissolves the subsurface minerals and emerges in the form of hot springs along the permeable fracture or fault zones.

scholarly journals Study of Air Quality at One of the World’s Most Densely Populated City Dhaka and its Suburban Areas

2019 ◽  
Vol 43 (1) ◽  
pp. 59-66
Author(s):  
Mohammad Lokman Hossain ◽  
Subrata Chandra Roy ◽  
Mithun Chandra Bepari ◽  
Bilkis Ara Begum
Keyword(s):  
Particulate Matter ◽  
Urban Area ◽  
Power Plants ◽  
Winter Season ◽  
Atmospheric Particulate Matter ◽  
Suburban Areas ◽  
Air Sampler ◽  
Pm10 And Pm2.5 ◽  
Academy Of Sciences ◽  
The City

Air borne particulate matter PM10 and PM2.5 were collected by using Mini Vol portable Air Sampler from the world most densely populated city Dhaka and its suburban areas over a period of January through December in 2016. This study revealed a comparison of atmospheric particulate matter (PM) of a highly polluted urban area to its two neighboring areas that accommodate heavy oil based power plants. In all three sites the quantity of PM decreases in summer reaching its lowest level in the month of July, however, it increases significantly in winter season. Despite the presence of the fuel based power plants the average concentrations of PM10 and PM2.5 at the city Dhaka surpasses its two neighbors Manikganj and Nawabganj. Interestingly, PM2.5/PM10 ratio is higher at the suburban areas than urban area. The study shows that for all the sites PM2.5 is approximately twice than that of WHO and USEPA. However, the values of PM2.5 is almost similar for Nawabganj and Manikganj but much higher for the Dhaka city especially during dry season . The Mass concentration of Black Carbon (BC) was also determined from the PM samples from Manikganj and Nawabganj. Journal of Bangladesh Academy of Sciences, Vol. 43, No. 1, 59-66, 2019

scholarly journals Performance Analysis of Air-to-Water Heat Pump in Latvian Climate Conditions

2014 ◽  
Vol 14 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Janis Kazjonovs ◽  
Andrejs Sipkevics ◽  
Andris Jakovics ◽  
Andris Dancigs ◽  
Diana Bajare ◽  
...  
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Residential Buildings ◽  
Winter Season ◽  
Pump Energy ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Heating Period ◽  
Climate Conditions ◽  
Eu Directive

Abstract Strategy of the European Union in efficient energy usage demands to have a higher proportion of renewable energy in the energy market. Since heat pumps are considered to be one of the most efficient heating and cooling systems, they will play an important role in the energy consumption reduction in buildings aimed to meet the target of nearly zero energy buildings set out in the EU Directive 2010/31/EU. Unfortunately, the declared heat pump Coefficient of Performance (COP) corresponds to a certain outdoor temperature (+7 °C), therefore different climate conditions, building characteristics and settings result in different COP values during the year. The aim of this research is to investigate the Seasonal Performance factor (SPF) values of air-to-water heat pump which better characterize the effectiveness of heat pump in a longer selected period of time, especially during the winter season, in different types of residential buildings in Latvian climate conditions. Latvia has four pronounced seasons of near-equal length. Winter starts in mid-December and lasts until mid-March. Latvia is characterized by cold, maritime climate (duration of the average heating period being 203 days, the average outdoor air temperature during the heating period being 0.0 °C, the coldest five-day average temperature being −20.7 °C, the average annual air temperature being +6.2 °C, the daily average relative humidity being 79 %). The first part of this research consists of operational air-towater heat pump energy performance monitoring in different residential buildings during the winter season. The second part of the research takes place under natural conditions in an experimental construction stand which is located in an urban environment in Riga, Latvia. The inner area of this test stand, where air-to-water heat pump performance is analyzed, is 9 m2. The ceiling height is 3 m, all external wall constructions (U = 0.16 W/(m2K)) have ventilated facades. To calculate SPF, the experimental stand is equipped with sensors which provide measurements for electricity consumption and gained heat energy.

Surface Nanocrystallization by Surface Mechanical Attrition Treatment

2008 ◽  
Vol 579 ◽  
pp. 91-108 ◽  
Author(s):  
N.R. Tao ◽  
Jian Lu ◽  
K. Lu
Keyword(s):  
Surface Layer ◽  
Grain Refinement ◽  
Mechanical Twinning ◽  
Surface Mechanical Attrition Treatment ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Tensile Fatigue ◽  
Mechanical Attrition ◽  
And Performance ◽  
Mechanical Twins

Based on strain-induced grain refinement, a novel surface mechanical attrition treatment (SMAT) technique has been developed to synthesize a nanostructured surface layer on metallic materials in order to upgrade their overall properties and performance without changing their chemical compositions. In recent several years, the microstructures and properties of surface layer were systematically investigated in various SMAT metals and alloys, including b.c.c., f.c.c. and h.c.p. crystal structures. Different grain refinement approaches and nanocrystalline formation mechanisms were identified in these deformed materials, involving dislocation activities, mechanical twinning and interaction of dislocations with mechanical twins. The properties of the surface layer were measured by means of hardness, tensile, fatigue and wear tests. The enhanced properties of the surface layer are mainly attributed to the strain-induced grain refinement. In this work, we reviewed the microstructures and properties of surface layer in the SMAT materials.

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