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121.
Surface air concentrations of (7)Be at a number of stations in Oceania show a distinct annual cycle. We apply a sinusoidal model to describe this cycle. The results show that peak (7)Be concentrations in surface air occur during early spring at tropical latitudes and during mid-to-late summer at middle latitudes. Comparison with available (90)Sr surface air data for the southern hemisphere indicates that stratosphere-to-troposphere exchange is an active atmospheric process controlling the (7)Be annual cycle throughout the Oceania region. Vertical transport of air within the troposphere also seems to influence the observed annual cycle. Seasonality in rainfall is not thought to control the annual cyclic behaviour of (7)Be in surface air.  相似文献   
122.
The selective catalytic reduction (SCR) rate of NO with N-containing reducing agents can be enhanced considerably by converting part of NO into NO2. The enhanced reaction rate is more pronounced even at lower temperatures by using an equimolar mixture of NO and NO2 (fast SCR reaction). The oxidation characteristics of NO over catalyst Pt/TiO2 have been determined in a fixed bed reactor (8 mm-ID) with different concentrations of oxygen, nitric oxide and nitrogen dioxide in the presence of 8% water. The conversion of NO to NO2 increases with increasing oxygen (O2) concentration from 3 to 12%, but it levels off at higher O2 concentrations. The NO conversion to NO2 decreases with increasing NO concentration and it also decreases by an addition of NO2 in the feed stream. Therefore, the oxidation of NO over Pt/TiO2 catalyst could be auto-inhibited by the reaction product of NO2. The effects of CO and SO2 on NO oxidation characteristics have also been determined. In fact, the presence of SO2 significantly suppresses oxidation of NO but due to the less stability of sulfate on anatase structure in TiO2, it becomes less significant. On the other hand, the presence of CO increases NO oxidation significantly due to the auto-inhibition effect by CO. Moreover, the effect of SO2/CO on NO oxidation has also been determined and it was observed that NO oxidation decreases with the increase in SO2/CO ratio.  相似文献   
123.
The ability of cadmium uptake by metal-resistant yeast, Candida tropicalis, from the liquid medium and wastewater was evaluated. The minimum inhibitory concentration of Cd2?+? against C. tropicalis was 2,500 mg L???1. The yeast also showed tolerance toward Zn2?+? (1,400 mg L???1), Ni2?+? (1,000 mg L???1), Hg2?+? (1,400 mg L???1), Cu2?+? (1,000 mg L???1), Cr6?+? (1,200 mg L???1), and Pb2?+? (1,000 mg L???1). The yeast isolate showed typical growth curves, but lag and log phases extended in the presence of cadmium. The yeast isolate showed optimum growth at 30°C and pH 8. The metal processing ability of the isolate was determined in a medium containing 100 mg L???1 of Cd2?+?. C. tropicalis could decline Cd2?+? 70%, 85%, and 92% from the medium after 48, 96, and 144 h, respectively. C. tropicalis was also able to remove Cd2?+? 40% and 78% from the wastewater after 6 and 12 days, respectively. Cd produced an increase in glutathione (GSH) and nonprotein thiol levels by 135% and 134% at 100-mg L???1 concentration, respectively. An increase in the synthesis of GSH is involved in metal tolerance, and the presence of increasing GSH concentrations may be a marker for high metal stress in C. tropicalis. C. tropicalis, which is resistant to heavy metal ions and is adaptable to the local environmental conditions, may be employed for metal detoxification operations.  相似文献   
124.
Food and Environmental Virology - Drinking water supplies in the developing world often serve as a biosphere for various organisms. Viral gastroenteritis is a neglected area of research in...  相似文献   
125.
Journal of Polymers and the Environment - In this study, carboxymethyl chitosan with gum Arabic (CG) based novel functional films containing Cinnamomum camphora seeds extract (CCSE) at varying...  相似文献   
126.
Environmental Fluid Mechanics - The principle theme of this study is to introduce a novel countermeasure to reduce the energy of the overflowing floodwater by utilization of a water cushion. For...  相似文献   
127.

Polymer materials are vulnerable to damages, failures, and degradations, making them economically unreliable. Self-healing polymers, on the other hand, are multifunctional materials with superior properties of autonomic recovery from physical damages. These materials are suitable for biomedical and tissue engineering in terms of cost and durability. Schiff base linkages-based polymer materials are one of the robust techniques owing to their simple self-healing mechanism. These are dynamic reversible covalent bonds, easy to fabricate at mild conditions, and can self-reintegrate after network disruption at physiological conditions making them distinguished. Here we review self-healing polymer materials based on Schiff base bonds. We discuss the Schiff base bond formation between polymeric networks, which explains the self-healing phenomenon. These bonds have induced 100% recovery in optimal cases.

  相似文献   
128.
Environmental Science and Pollution Research - COVID-19, declared by the World Health Organization (WHO) to be a pandemic, has affected greenhouse gas emissions and contributed to the uncertainty...  相似文献   
129.
Environmental Science and Pollution Research - Climate change is a long-lasting change in the weather arrays across tropics to polls. It is a global threat that has embarked on to put stress on...  相似文献   
130.
Environmental Science and Pollution Research - Sunflower plants need nitrogen consistently and in higher amount for optimum growth and development. However, nitrogen use efficiency (NUE) of...  相似文献   
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