Aerosol Optical and Radiative Properties Observed at Anmyeon and Jeju, Korea in the Spring of 2000 and 2001

The radiative properties of atmospheric aerosols are determined by their masses, chemical characteristics, and optical properties, such as aerosol optical depth (AOD), Åstrom;ngström parameter (α) and single scattering albedo (SSA). In particular, the aerosol optical properties determine the surface temperature perturbation that may give some information in understanding regional atmospheric radiative forcing. To understand the radiative forcing and regional source of an aerosol, the present study focused on the analysis of the aerosol optical properties based on two different observations in the spring season, during the special Asian dust storm period. The Korean Global Atmosphere Watch Observatory (KGAWO), at Anmyeon Island, and the ACE-Asia super-site, at Gosan, Jeju Island, have measured radiations and aerosols since 2000. The sites are located in the mid-west and south of the Korean peninsula, which are strongly affected by the Asian dust coming from China every spring. The aerosol optical properties, measured by ground-based sun and sky radiometers, over both sites were analyzed to gain an understanding of the radiation and climate properties.The probability distributions of the aerosol optical depths were rather narrow, with a modal value of approximately 0.38 at both sites during 2001 and 2002. The Ångström parameter frequency distributions showed two peaks at Anmyeon GAW, but only one peak at the Jeju ACE-Asia super site. One peak, around 0.63, characterizes the situation of a day having Asian dust, the second peak, around 1.13, corresponded to the relatively dust-free cases. The correlation between the aerosol optical depth and the Ångström exponents resulted in a wide range of the Ångström parameter, α, over a wide range of optical depths at Anmyeon, whereas a narrow range of α, with moderate to low values for the AOD at Jeju. Under dust free conditions the single scattering albedo (SSA) decreased with wavelength, while in the presence of Asian dust,the SSA either stayed neutral, or increased slightly with wavelength at Anmyeon, and showed higher value than Jeju. The change in the surface temperature was highly correlated with increases in the aerosol optical depth at Anmyeon to a greater extent than at Jeju.     

Inactivation of SARS-CoV-2 by Ozonated Glycerol

We evaluated the SARS-CoV-2-inactivation activity of ozonated glycerol (OG). When a viral solution with 1% fetal bovine serum (FBS) was mixed with test solutions at a ratio of 1:19 and incubated for 20 s, OG with ozone concentrations of over 1000 ppm inactivated ≥ 94.38% of the virus. Extension of the reaction time to 1 h led to the inactivation of ≥ 99.82% of the virus (the viral titer was below the detection limit). Extension to 24 h resulted in concentrations over 200 ppm OG inactivating ≥ 99.87% of the virus (the viral titers were below the detection limit). Next, viral solutions with 1, 20, and 40% FBS were mixed with test solutions at a ratio of 1:19 and incubated for 5 min. Whereas the virucidal activity of 500 ppm OG was very limited in the presence of 1% FBS (79.47% inactivation), it increased in the presence of 20 and 40% FBS (95.13 and 97.95% inactivation, respectively; the viral titers were not below the detection limit). Meanwhile, over 1000 ppm OG inactivated ≥ 99.44% of the virus regardless of the FBS concentration (the viral titers were below the detection limit). Extension of the reaction time to 1 h led to 500 ppm OG inactivating ≥ 99.91 and ≥ 99.95% of the virus with 20 and 40% FBS, respectively (the viral titers were below the detection limit). These results suggested that OG might be useful as a virucidal agent against SARS-CoV-2.

     

Methyl methacrylate (MMA) and alumina recovery from waste artificial marble powder pyrolysis

Journal of Material Cycles and Waste Management - Owing to various advantages of artificial marble compared to natural marble, its application has been rising exponentially, which has resulted in...     

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO₂ absorption. A 2-amino- 2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO₂ than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH₃), respectively. The reaction rate constant for CO₂ absorption by the AMP/KIER-C3 solution was determined by the following equation: k_2,AMP/C3 = 7.702×10⁶ exp (-2248.03/T). A CO₂ loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO₂ absorption capability of AMP.     

A feasibility study of thermal hydrolysis by-products as barrier layer materials in the final cover system for a landfill

Most sludge has historically been disposed of in landfills and by ocean dumping but, because of its heavy metal content, this will be totally banned in Korea starting in 2012, based on the London Dumping Convention. Therefore, treatment and disposal methods that are environmentally friendlily are urgently required. The recycling of sewage sludge is a good treatment method for solving sludge problems in an environmentally friendly way. In this study, physical and environmental tests were conducted to evaluate the feasibility of using the by-products of thermal hydrolysis of sewage sludge as barrier layer materials in the final cover systems for landfills. In addition, testing methods for freezing-thawing (KS F 2332) and wetting-drying (KS F 2330) cycles were conducted to assess the effects of cold and hot soil climates starting from pavement. These tests yielded positive results for alternative materials for the barrier layer in a final cover system for a landfill.     

Meteorological effects on the evolution of high ozone episodes in the greater Seoul area

Three high O3 episodes--7 days in 1992 (July 3-July 9), 9 days in 1994 (July 21-July 29), and another 3 days in 1994 (August 22-August 24)--were selected on the basis of morning (7:00 a.m.-10:00 a.m.) average wind direction and speed and daily maximum O3 concentrations in the greater Seoul, Korea, of 1990-1997. To better understand their characteristics and life cycles, surface data from the Seoul Weather Station (SWS) and surface and 850-hPa wind field data covering northeast Asia around the Korean Peninsula were used for the analysis. In the July 1992 episode, westerly winds were most frequent as a result of the influence of a high-pressure system west of the Korean Peninsula behind a trough. In contrast, in the July 1994 episode, easterly winds were most frequent as a result of the effect of a typhoon moving north from the south of Japan. Despite different prevailing wind directions, the peak O3 concentrations for each episode occurred when a sea/land breeze developed in association with weak synoptic forcing. The August 1994 episode, which was selected as being representative of calm conditions, was another typical example in which a well-developed     

Application of eggshell waste for the immobilization of cadmium and lead in a contaminated soil

Liming materials have been used to immobilize heavy metals in contaminated soils. However, no studies have evaluated the use of eggshell waste as a source of calcium carbonate (CaCO₃) to immobilize both cadmium (Cd) and lead (Pb) in soils. This study was conducted to evaluate the effectiveness of eggshell waste on the immobilization of Cd and Pb and to determine the metal availability following various single extraction techniques. Incubation experiments were conducted by mixing 0–5% powdered eggshell waste and curing the soil (1,246 mg Pb kg^?1 soil and 17 mg Cd kg^?1 soil) for 30 days. Five extractants, 0.01 M calcium chloride (CaCl₂), 1 M CaCl₂, 0.1 M hydrochloric acid (HCl), 0.43 M acetic acid (CH₃COOH), and 0.05 M ethylendiaminetetraacetic acid (EDTA), were used to determine the extractability of Cd and Pb following treatments with CaCO₃ and eggshell waste. Generally, the extractability of Cd and Pb in the soils decreased in response to treatments with CaCO₃ and eggshell waste, regardless of extractant. Using CaCl₂ extraction, the lowest Cd concentration was achieved upon both CaCO₃ and eggshell waste treatments, while the lowest Pb concentration was observed using HCl extraction. The highest amount of immobilized Cd and Pb was extracted by CH₃COOH or EDTA in soils treated with CaCO₃ and eggshell waste, indicating that remobilization of Cd and Pb may occur under acidic conditions. Based on the findings obtained, eggshell waste can be used as an alternative to CaCO₃ for the immobilization of heavy metals in soils.     

Reproductive biology of the common shrimp Crangon crangon (Decapoda: Crangonidae) in the central Irish Sea

Aspects of the reproductive biology of the common shrimp Crangon crangon (L.) were studied in Port Erin Bay, Isle of Man, Irish Sea. Size at sexual maturity was determined from the proportions of ovigerous females and of females with maturing ovaries. The size at which 50% of females are mature is estimated (±95% confidence intervals) as 12.5±0.48 mm carapace length. Based on the proportions of ovigerous females and of mature females, the main breeding season was from January to June. Mean ovarian dry weights indicated two broods (winter and summer), with females bearing winter broods (WB) having higher gonad indices than those with summer broods (SB). WB females with non-eyed eggs and with eyed eggs differed in the regression of ovarian dry weight on carapace length, indicating preparation for laying a second brood. In both broods the moult stages of berried females were related to egg stage. Moulting will occur following the release of the brood. During embryonic development, mean egg length and egg volume were larger in all stages, and the mean dry weight of individual eggs of all stages heavier, in WB than in SB; there was no difference in egg number, however. Consequently, reproductive investment, the proportion of female weight devoted to egg production, was 67% higher in WB (0.20±0.04) than in SB (0.12±0.03). There is a significant effect of egg volume on brood weight, but not on egg number. In both broods, egg number was a negatively allometric function of female body size in non-eyed eggs and an isometric function of female body size in eyed eggs. Brood mortality during incubation was higher in SB (17%) than WB (10%). Differences in the reproductive variables and investment between the two broods of C. crangon are discussed in the light of reproductive strategies and life history.Communicated by J.P. Thorpe, Port Erin     

Development of intelligent sorting system realized with the aid of laser-induced breakdown spectroscopy and hybrid preprocessing algorithm-based radial basis function neural networks for recycling black plastic wastes

Plastic recycling has been the key issue for reducing environmental problems and resolving resource depletion. To improve the recovery rate of plastics, the plastic wastes are correctly identified according to their resin type. However, the identification system, which is able to identify black plastics according to not only the type of black plastics but also the grade of resins correctly, has not been introduced. In this paper, laser-induced breakdown spectroscopy, intelligent algorithms and preprocessing algorithms are used to improve the identification of black plastics such as polypropylene, polystyrene (PS), and acrylonitrile butadiene styrene (ABS). The laser-induced breakdown spectroscopy is capable of obtaining the characteristic spectrum regardless of material’s physical state. To extract the new features which are very valuable to improving learning performance, increasing computational efficiency, and building better generalization models from the obtained spectra through laser-induced breakdown spectroscopy, the hybrid preprocessing algorithm, composed of principal component analysis and independent component analysis, is used. In addition, the intelligent algorithm named the extended radial basis function neural networks inheriting the advantages of fuzzy theory and neural networks is used to identify black plastic samples into several categories with respect to their resins. The proposed identification system, composed of three parts such as laser induced breakdown spectroscopy, hybrid preprocessing algorithms, and an efficient intelligent classification algorithm, is able to show the synergy effect on the black plastic identification problem. From several experimental results, it can be seen that the identification system based on laser-induced breakdown spectroscopy and the intelligent algorithm is used for identification of black plastics by resin type.     

Assessment of characteristic distribution of PCDD/Fs and BFRs in sludge generated at municipal and industrial wastewater treatment plants

The presence of polychlorinated dibenzo-p-dioxins and furan (PCDD/Fs) and brominated flame retardants (BFRs) in sludge generated at municipal wastewater treatment plants (MWTPs) and industrial wastewater treatment plants (IWTPs) was investigated. The concentrations of these pollutants were in the following ranges: 5.38-7947 ng kg⁻¹ dw (0.02-49.9 ng WHO-TEQ kg⁻¹ dw) for 17 PCDD/Fs, 17.5-66 761 μg kg⁻¹ dw for 27 polybrominated diphenyl ethers (PBDEs), 1.55-29 604 μg kg⁻¹ dw for hexabromocyclododecanes (HBCDs) (α-, β-, and γ-diastereomers), and 4.01-618 μg kg⁻¹ dw for tetrabromobisphenol A (TBBPA). Generally, the levels of each compound in the sewage-sludge samples were higher than those in the industrial-sludge samples with some exceptions. The characteristic distribution profiles of target compounds were observed for different types of sludge and different sources of wastewater. High-chlorinated PCDD/Fs were dominant in all samples except those from the textile industry. The distribution of the BFRs in industrial-sludge samples varied, whereas that of the BFRs in sewage-sludge samples was consistent. The proportion of penta-BDEs in sewage sludge was higher than that in industrial sludge, even though BDE-209 was the most dominant congener in all the samples. For HBCDs, the distribution of diastereomers (α-, β-, and γ-HBCD) was similar across sludge samples that had the same source of wastewater and treatment processes.