Search results for "atmosphere"
showing 10 items of 673 documents
Students’ Experiences of Studying Music in Small Groups
2015
Abstract The transition to the group instruction in teaching to play music has created a need to understand the significance of the group in connection with studying to play music. What kind of significance do the students in the class teachers’ adult education give to the group in connection with studying to play music? The aim of this study is to describe and to understand the significance given to the small group by teacher students in connection with studying to play to music, learning in small groups and the challenges and possibilities brought on by the group learning to the pedagogics. The material of the study consists of 17 students’ writings. The writings have been created as answ…
UKIRT Observations of the Impact and Consequences of Comet Shoemaker–Levy 9 on Jupiter☆
1997
The observation of Comet Shoemaker-Levy 9's collision with Jupiter in July of 1994 by the United Kingdom Infrared Telescope (UKIRT) produced spectroscopic data of high quality. Analysis of the data for Impact C has produced the first temperature curve that covers such an event, from the first visibility of the plume above the limb through to the settling down of the ejected gas onto the upper jovian atmosphere. Temperatures derived from methane emission show that 5 min after impact, a plume some 6500 km across was heated to similar to 1400 K. At its maximum spatial extent similar to 12 min after impact, a region of Jupiter's atmosphere similar to 45,000 km west from the impact site of the m…
The Atmospheric Aerosol and Trace Gases
2010
From Chapter 6, it is evident that an understanding of the cloud forming processes in the atmosphere requires knowledge of the physical and chemical characteristics of the atmospheric aerosol. In dicussing this gaseous suspension of solid and liquid particles, it is customary to include all gases except water vapor, and all solid and liquid particles except hydrometeors, i.e., cloud and raindrops, and ice particles.
In-situ monitoring by Raman spectroscopy of the thermal doping of graphene and MoS2 in O-2-controlled atmosphere
2017
The effects of temperature and atmosphere (air and O2) on the doping of monolayers of graphene (Gr) on SiO2 and Si substrates, and on the doping of MoS2 multilayer flakes transferred on the same substrates have been investigated. The investigations were carried out by in situ micro-Raman spectroscopy during thermal treatments up to 430 °C, and by atomic force microscopy (AFM). The spectral positions of the G and 2D Raman bands of Gr undergo only minor changes during treatment, while their amplitude and full width at half maximum (FWHM) vary as a function of the temperature and the used atmosphere. The thermal treatments in oxygen atmosphere show, in addition to a thermal effect, an effect a…
Graphene p-Type Doping and Stability by Thermal Treatments in Molecular Oxygen Controlled Atmosphere
2015
Doping and stability of monolayer low defect content graphene transferred on a silicon dioxide substrate on silicon are investigated by micro-Raman spectroscopy and atomic force microscopy (AFM) during thermal treatments in oxygen and vacuum controlled atmosphere. The exposure to molecular oxygen induces graphene changes as evidenced by a blue-shift of the G and 2D Raman bands, together with the decrease of I2D/IG intensity ratio, which are consistent with a high p-type doping (∼1013 cm-2) of graphene. The successive thermal treatment in vacuum does not affect the induced doping showing this latter stability. By investigating the temperature range 140-350 °C and the process time evolution, …
Environment assisted photoconversion of luminescent surface defects in SiO 2 nanoparticles
2017
Abstract Time-resolved photoluminescence investigation on SiO 2 nanoparticles was carried out in controlled atmosphere, with the aim to discern the effects induced on the typical blue luminescence band by high power UV Nd:YAG laser photons (4.66 eV) and by some selected molecular species of the air (O 2 , N 2 , CO 2 , H 2 O). These factors ultimately determine both the brightness and photostability of the emitting defect, so as to limit the unique and attracting potentialities offered by this system in many applicative fields. Here it is highlighted that the effects due to photons and molecules, singularly considered, are not additive, the radiation being more dramatic in reducing the emiss…
Improvement of plum storage with modified atmosphere packaging
2010
Post-harvest supply chain is a critical point for agro-food marketing. The management of freshness in the storage is fundamental to maintain high profits in the agro-food sector to improve the distribution and to respond to retailers and consumers' requirements. Plums are considered to have a climacteric-ripening pattern, in which ethylene is the hormone responsible for ripening. Modified atmosphere (MA) storage is a method helpful to maintain the natural quality of fruits. MA added to low temperatures influence fruit metabolism and reduce ethylene production, weight losses, hardness of pulp, preserving vitamins and organic acids. The objective of this study was to increase the condition of…
West African Monsoon influence on the summer Euro-Atlantic circulation
2011
International audience; The West African Monsoon (WAM) influence on the interannual variability of the summer atmospheric circulation over North Atlantic and Europe is investigated over the period 1971-2000. A set of sensitivity experiments performed through the Arpege-Climat atmospheric general circulation model is analyzed, using the so-called "grid-point nudging" technique, where the simulated atmospheric fields in the WAM region are relaxed towards the ERA40 reanalysis. Observations confirm that a sizable part of the Euro-Atlantic circulation variability is related to the WAM, with anomalies of reinforced convection in the Sudan-Sahel region associated with positive North Atlantic Oscil…
Power spectrum of turbulent convection in the solar photosphere
2020
The solar photosphere provides us with a laboratory for understanding turbulence in a layer where the fundamental processes of transport vary rapidly and a strongly superadiabatic region lies very closely to a subadiabatic layer. Our tools for probing the turbulence are high-resolution spectropolarimetric observations such as have recently been obtained with the two balloon-borne SUNRISE missions, and numerical simulations. Our aim is to study photospheric turbulence with the help of Fourier power spectra that we compute from observations and simulations. We also attempt to explain some properties of the photospheric overshooting flow with the help of its governing equations and simulations…
Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin
2018
Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM …