Search results for "content"

2017

Abstract. During free fall in clouds, ice hydrometeors such as snowflakes and ice particles grow effectively by riming, i.e., the accretion of supercooled droplets. Volatile atmospheric trace constituents dissolved in the supercooled droplets may remain in ice during freezing or may be released back to the gas phase. This process is quantified by retention coefficients. Once in the ice phase the trace constituents may be vertically redistributed by scavenging and subsequent precipitation or by evaporation of these ice hydrometeors at high altitudes. Retention coefficients of the most dominant carboxylic acids and aldehydes found in cloud water were investigated in the Mainz vertical wind tu…

A Theoretical Study of the Wet Removal of Atmospheric Pollutants. Part III: The Uptake, Redistribution, and Deposition of (NH4)2SO4Particles by a Con…

1988

Abstract Our model for the scavenging of aerosol particles has been coupled with the two-dimensional form of the convective cloud model of Clark and Collaborators. The combined model was then used to simulate a convective warm cloud for the meteorological situation which existed at 1100 LST 12 July 1985 over Hawaii; assuming an aerosol size distribution of maritime number concentration and of mixed composition with (NH4)2SO4 as the soluble compound. A shallow model cloud developed 26 min after the onset of convection leading to moderate rain which began after 45 min and ended after 60 min. Various parameters which characterize the dynamics and micophysics of the cloud, as well as the scaven…

The Effect of Intense Air Drying on Material Distribution and Quality in Coated Papers

2003

Abstract The aim of this study was to find out what will happen to paper coating quality and material gradients if coating is dried in one air dryer at a high convection rate (150 kg/m2h). Different printing papers were coated, calendered and printed with pilot machines. The binder and pigment gradients of the coated, and also printed, samples were analyzed with LIPS (Laser Induced Plasma Spectrometry). It was found that drying affects the migration of starch, but not latex. Total air drying can be used to dry printing papers, if air temperature, velocity and moisture content can be separately controlled. The control of web temperature is more important for paper quality formation in a coat…

2018

This study presents new ways of visualising technology-enhanced collaborative inquiry-based learning (CIBL) processes in an undergraduate physics course. The data included screen-capture videos fro...

2021

Staying at the front line in learning research is challenging because many fields are rapidly developing. One such field is research on the temporal aspects of computer-supported collaborative learning (CSCL). To obtain an overview of these fields, systematic literature reviews can capture patterns of existing research. However, conducting systematic literature reviews is time-consuming and do not reveal future developments in the field. This study proposes a machine learning method based on topic modelling that takes articles from a systematic literature review on the temporal aspects of CSCL (49 original articles published before 2019) as a starting point to describe the most recent deve…

Collaborative 3D learning games for future learning: teachers’ instructional practices to enhance shared knowledge construction among students

2013

Collaborative games will enable new kinds of possibilities for learning. In the future, the goal of game-based learning should be to introduce new ideas and deepen in-depth understanding of learners. However, studies have shown that shared high-level knowledge construction is a challenging process. Moreover, thus far, few empirical studies have examined what constitutes the teacher’s role in games. The focus of this paper is to investigate teachers’ real-time instructional activities in a scripted 3D game setting. Our hypothesis is that groups with real-time teacher instruction will come up with more shared knowledge construction that can be considered productive than groups studying withou…

Teacher coping profiles in relation to teacher well-being : a mixed method approach

2021

The aim was to investigate teachers’ coping profiles and their relations to teacher well-being. Questionnaire data was collected from 107 Finnish teachers. Theory-driven content analysis of teachers’ responses revealed three coping categories: problem-focused, emotion-focused and mixed problem- and emotion-focused. Next, teachers were categorized into four coping profiles by using latent profile analysis: Low-coping users (21%), Problem-focused-coping users (15%), High-coping users (12%) and Emotion-focused-coping users (52%). Low-coping-user teachers reported less stress and fewer depressive symptoms and sleep problems compared to Emotion-focused-coping users. Using a compact amount of cop…

Biomass, litterfall and nutrient content in Castanea sativa coppice stands of southern Europe

1996

Les biomasses et les mineralomasses, les retombees de litiere et la restitution au sol de bioelements par leur intermediaire ont ete etudiees dans des peuplements de Castanea sativa Mill en Espagne (province de Salamanque), en Italie (massif de l'Etna) et en France (Cevennes). Les meilleurs correlations et resultats ont ete trouves avec des regressions allometriques de type: Y (biomasse) = aX (diametre tronc a 1,30 m) b . Les parametres des differentes equations de regression sont semblables et tres proches pour les châtaigniers de France et d'Italie. La principale source de differences, au niveau stationnel, resulte de la repartition differente des arbres en fonction des classes de diametr…

Thermally Induced Structural Modification of Silica Nanoparticles Investigated by Raman and Infrared Absorption Spectroscopies

2010

We report an experimental investigation by Raman and infrared (IR) absorption spectroscopies on the structural modifications induced by isochronal thermal treatments on amorphous SiO2 nanoparticles (fumed silica). In particular, three different commercial types of this material, characterized by particle mean diameters of 7, 14, and 40 nm, were subjected to thermal treatments from 100 up to 1000 °C. We found that some properties of fumed silica, such as the SiOSi mean bond angle, ring size distribution, and surface adsorbed water content, are drastically different from those of common bulk silica materials and intimately related to the particles' dimension. The SiOSi mean bond angle, probed…

Instructor Presence in a Virtual Classroom

2021

Abstract Synchronous online learning platforms have been used actively during the COVID-19 period. They have opened possibilities for online learning and interaction, but have also posed new challenges for instructors. This article provides insights into one teacher’s interactions and examines how the instructor presence is expressed in the teachers’ activities in virtual classrooms in higher education. Instructor presence is investigated using the social and teaching presence indicators of the community of inquiry (CoI) framework. Twelve hours of interactions across six online classes were recorded, transcribed, and analysed using content analysis. The findings suggest that indicators of t…