Size distribution and spectral responses of atmospheric aerosol measured by single mobility particle sizer (SMPS) and multi wavelength photoacoustic spectrometer (4λ-PAS)

This campaign was made under wintry urban meteorological conditions from late winter until early spring of 2015, in Budapest, the capital of Hungary. Optical absorption coefficient (OAC) is generally measured by two different methodologies. One was the most commonly used Aethalometer [1]. The other was the recently developed multi wavelength photoacoustic instrument (4-λ-PAS) [2]. The size distribution and number concentration of ambient aerosol was measured by a single mobility particle sizer (SMPS). The measurement period could be classified normal days and nucleation days. The correction factor of filter based transmission measurement was experimentally determined using photoacoustic instrument as reference. Both the correction factor and the spectral responses were found to be characteristic for normal and nucleation days

Conjugation between 3D and 2D aromaticity: does it really exist? The case of carborane-fused heterocycles

Although several synthesized icosahedral carborane fused 2D π-ring systems are known, and even considerable conjugation has been noted between them in some cases, the phenomenon itself is not fully understood. Based on the results of our computational study, it can be concluded that the 2D aromatic character of the fused (exo) five-membered ring is low, even in cases where significant conjugation was proposed in previous studies. Moreover, the carborane moiety constricts the bonding properties of the exo ring, thus prohibiting or promoting different Lewis resonance structures. These results will shed further light on the design and electronic modulation of new carborane-based materials

Investigation of size distribution and spectral responses of diesel engine emitted carbonaceous particulate using multi waveleng photoacoustic spectroscopy (4λ-PAS) and single mobility particle sizer (SMPS)

This work discuss some results of the extended measurement campaign focussing the in-situ microphysical characterisation of the emitted diesel particulates of different fuel types at diferent operational condition of diesel engine. For measureemnt of the spectral repsonses and the size distribution of the diesel emission customised multi wavelength photoacoustic spectrometer and single commercially single mobility particle sizer were uesd. Basee on the size distribution data we experimentally demonstarte that at idle the emitted aerosol assembly have bimodal distribution in all type of fuel and working point of engine. We also demonstarte that the spectral responses of the diesel aerosol is characterisits for the type of fuel and the operational condition of engine. Using posterior temperature treatement we manifest that especially at idle the volatile fraction of the emitted aerosol can dominantly removed above 150C temeperature. Finally, we also experimentalla demonstarted that the biodiesel content of the diesel fuel even in its relatively small blending even in a relatively small (<7%) mixing ratio can significantly modify the climate and health relevant microphysical feature of the diesel emission