Search results for "Haze"

Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of pm<sub>2.5</sub> from xi'an, northwestern c…

2018

Abstract. The sources, formation mechanism and amount of organosulfates (OS) in atmospheric aerosol are not yet well understood, partly due to the lack of authentic standards for quantification. In this study, we report an improved robust procedure for the synthesis of organosulfates with different functional groups. Nine authentic organosulfate standards were synthesized and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate, and hydroxyacetone sulfate) were used to quantify their ambient concentrations. The authentic standards and ambient aerosol samples were analyzed using an optimized ultra performance liquid chromatography–electrospray ionization-tandem mass spectrom…

DEALING WITH RISK IN AGRICULTURE: A CROP LEVEL ANALYSIS AND MANAGEMENT PROPOSAL FOR ITALIAN FARMS

2020

Risk management plays a critical role in agriculture, which is particularly exposed to multiple and heterogeneous risk factors. In addition to the traditional basic risks that generally characterize any business venture, agriculture faces external factors, generally difficult to control and with a strong impact on farm profitability. These are firstly environmental (pests and diseases) and climatic conditions that affect the quantity and quality of agricultural production, but also the structural constraints of the agricultural market, which is characterised by a high degree of supply rigidity, price volatility and inelasticity of demand. This leads to the need to implement risk management …

A PH-functionalized polyphosphazene: a macromolecule with a highly flexible backbone.

2006

Solution processable high band gap hosts based on carbazole functionalized cyclic phosphazene cores for application in organic light‐emitting diodes

2011

A new class of solution processable dendrimers based on cyclic phosphazene (CP) cores have been prepared and used as host materials for blue and green organic light emitting diodes (OLEDs). The dendrimers are prepared in high yield from minimal step reactions, are soluble in common solvents for solution processing, are amorphous, and have excellent thermal properties necessary for application in OLEDs. OLED efficiencies of 10.3 cd/A (4.2 Im/W) and 35.3 cd/A (33.5 Im/W) were achieved using commercially available Flrpic and Ir(mppy) 3 as blue and green phosphorescent emitters, respectively. These efficiencies were 2x higher than control devices prepared using poly(N-vinylcarbazole), the most …

L'affaire Doize (1861-1862). Du trou noir d'Hazebrouck à la réforme de la procédure pénale

2004

Measurement report of the change of PM2.5 composition during the COVID-19 lockdown in urban Xi'an: Enhanced secondary formation and oxidation

2021

Enhanced secondary aerosol formation was observed during the COVID-19 lockdown in Xi'an, especially for polluted episodes. More oxidized‑oxygenated organic aerosol (MO-OOA) and sulfate showed the dominant enhancements, especially in large particle-mode. Meanwhile, relative humidity (RH) showed a positive promotion on the formation of sulfate and MO-OOA during the lockdown, but had no obvious correlation with less oxidized‑oxygenated organic aerosol (LO-OOA) or nitrate. Organosulfurs (OS) displayed a higher contribution (~58%) than inorganic sulfate to total sulfate enhancement in the polluted episode during the lockdown. Although the total nitrate (TN) decreased during the lockdown ascribin…

Discussion of “Modified Hazen–Williams and Darcy–Weisbach Equations for Friction and Local Head Losses along Irrigation Laterals” by John D. Valiantz…

2007

Arctic haze - characterization of aircraft collected supermicron particles of different haze layers over the Beaufort Sea

1997

Severe Pollution in China Amplified by Atmospheric Moisture

2017

AbstractIn recent years, severe haze events often occurred in China, causing serious environmental problems. The mechanisms responsible for the haze formation, however, are still not well understood, hindering the forecast and mitigation of haze pollution. Our study of the 2012–13 winter haze events in Beijing shows that atmospheric water vapour plays a critical role in enhancing the heavy haze events. Under weak solar radiation and stagnant moist meteorological conditions in winter, air pollutants and water vapour accumulate in a shallow planetary boundary layer (PBL). A positive feedback cycle is triggered resulting in the formation of heavy haze: (1) the dispersal of water vapour is cons…

Scattered Radiation in the Atmosphere and the Natural Aerosol

1964

Publisher Summary This chapter deals with problems of scattered atmospheric radiation, with regard to the haze in the atmosphere. The impressive phenomenon of the tint of the sky, which varies with the time of day and with the weather situation, has long stimulated the investigation of the radiation of the sky. As it is known that the sky radiation is in part, strongly polarized and that the degree of polarization is subjected to characteristic variations, these facts are included in the investigation. The atmospheric transparency for radiation and especially the radiation effects as related to aerosols of certain sizes are of fundamental importance. Reflected and scattered radiations are e…