Masses, luminosities and dynamics of galactic molecular clouds

Star formation in galaxies takes place in molecular clouds and the Milky Way is the only galaxy in which it is possible to resolve and study the physical properties and star formation activity of individual clouds. The masses, luminosities, dynamics, and distribution of molecular clouds, primarily giant molecular clouds in the Milky Way are described and analyzed. The observational data sets are the Massachusetts-Stony Brook CO Galactic Plane Survey and the IRAS far IR images. The molecular mass and infrared luminosities of glactic clouds are then compared with the molecular mass and infrared luminosities of external galaxies

Urban air pollution, climate and its impact on asthma morbidity

AbstractObjectiveTo study the mechanism of formation of air quality and to determine the impact of the studied factors on asthma morbidity in Vladivostok.MethodsThe evaluation of air pollution in Vladivostok was done using long-term (2008–2012) monitoring data (temperature, humidity, atmospheric pressure, wind speed, etc.). The levels of suspended particulate matter, nitrogen and sulfur dioxide, carbon monoxide, ammonia, formaldehyde (mg/m3) in six stationary observation posts were assessed. We studied the aerosol suspensions of solid particles, which were collected during snowfall from precipitation (snow) and air in 14 districts with different levels of anthropogenic impact. Melted snow was analyzed on laser granulometry. The impact of air pollution on the distribution of asthma morbidity was evaluated in various age groups by data of federal statistical observation obtained from 8 adults and 7 children municipal clinics in Vladivostok (2008–2012).ResultsThe content of suspended particulate components of pollution remained more stable, due to the features of atmospheric circulation, rugged terrain and residential development. The nano- and micro-sized particles (0–50 μm), which can absorb highly toxic metals, prevail in dust aerosols. These respirable fractions of particles, even in small doses, can contribute to the increase in asthma morbidity in the city.ConclusionsWe determined that asthma morbidity depends from general air pollution (in the range of 18.3%). It was detected that the highest age-specific dependence is associated with the content of particulate matter, carbon monoxide and nitrogen dioxide in air

Binder free and flexible asymmetric supercapacitor exploiting Mn3O4 and MoS2 nanoflakes on carbon fibers

Emerging technologies, such as portable electronics, have had a huge impact on societal norms, such as access to real time information. To perform these tasks, portable electronic devices need more and more accessories for the processing and dispensation of the data, resulting in higher demand for energy and power. To overcome this problem, a low cost high-performing flexible fiber shaped asymmetric supercapacitor was fabricated, exploiting 3D-spinel manganese oxide Mn3O4 as cathode and 2D molybdenum disulfide MoS2 as anode. These asymmetric supercapacitors with stretched operating voltage window of 1.8 V exhibit high specific capacitance and energy density, good rate capability and cyclic stability after 3000 cycles, with a capacitance retention of more than 80%. This device has also shown an excellent bending stability at different bending conditions

Reverse Micelle Strategy for the Synthesis of MnOx-TiO2Active Catalysts for NH3-Selective Catalytic Reduction of NOxat Both Low Temperature and Low Mn Content

MnOx-TiO2catalysts (0, 1, 5, and 10 wt % Mn nominal content) for NH3-SCR (selective catalytic reduction) of NOxhave been synthesized by the reverse micelle-assisted sol-gel procedure, with the aim of improving the dispersion of the active phase, usually poor when obtained by other synthesis methods (e.g., impregnation) and thereby lowering its amount. For comparison, a sample at nominal 10 wt % Mn was obtained by impregnation of the (undoped) TiO2sample. The catalysts were characterized by using an integrated multitechnique approach, encompassing X-ray diffraction followed by Rietveld refinement, micro-Raman spectroscopy, N2isotherm measurement at −196 °C, energy-dispersive X-ray analysis, diffuse reflectance UV-vis spectroscopy, temperature-programmed reduction technique, and X-ray photoelectron spectroscopy. The obtained results prove that the reverse micelle sol-gel approach allowed for enhancing the catalytic activity, in that the catalysts were active in a broad temperature range at a substantially low Mn loading, as compared to the impregnated catalyst. Particularly, the 5 wt % Mn catalyst showed the best NH3-SCR activity in terms of both NOxconversion (ca. 90%) and the amount of produced N2O (ca. 50 ppm) in the 200-250 °C temperature range

Electrical Properties of Meso-Porous Silicon: from a surface effect to Coulomb Blockade and more

Abstract: since the Volker Lehmann's paper "Resistivity of Porous Silicon: a surface effect" published in 1995 [1], a great deal of efforts has been produced in understanding the basic mechanisms ruling the electron transport in Si mesostructures and how these phenomena are affected by external environment. After more than 10 years, new experimental evidences and physical insights have been obtained, like gas sensitivity [2], chemisorption phenomena [3], Coulomb blockade [4] and glassy dynamics In the first half of the '90s, the most studied porous silicon morphology was from high resistivity p-type wafers, because of the high luminescence efficiency. The Lehmann's paper on electrical properties of porous silicon from p+ doped wafers, addressed few unanswered crucial questions regarding resistivity, impurity role, carrier freeze out and surface conditioning proposing a microscopic model of transport in mesoPS, in analogy to submicron channels of CMOS devices, whose figures of telegraph noise are affected by single charge trapping at the oxide-semiconductor interface. In 1999, the first report of strong interaction between mesoporous p+ silicon was announced in Strasbourg, EMRS by our group The successive years were so devoted to a fundamental study of mesoporous silicon in interaction with gas, by means of IR spectroscopy, ESR, NMR and ab-initio calculations Since the former paper of 1999 other groups contributed to study the phenomenon of NO 2 interaction with detailed papers on IR spectroscopy and Drude effect due to free carriers restored by nitrogen dioxid